Research among 40 marketers shows considerable variation, from largely agency-led structures to substantial in-house capability.
What dominates is specialisation: creative, media and performance work is usually split between different agencies, while internal teams keep strategic oversight.
Look closer, and the picture gets more interesting. Where the work sits, and why, varies enormously.
The research suggests there is no ideal combination model. Industry, internal capability, data requirements and the balance between brand building and performance all influence operational ownership.
Take a leading insurance marketer whose model leans firmly in-house.
Brand strategy, digital performance management, data science, technology and studio work all sit inside the business. Agencies handle above-the-line creative, media buying and specialist research.
You might expect a performance powerhouse. Yet only about 14% of this in-house team is dedicated to performance marketing. Why does it work? Proximity.
“An internal team isn’t just in the building; it’s embedded in the infrastructure of the business,” says Johanna McDowell, CEO of the Independent Agency Search & Selection Company (IAS).
“When performance data shows that something is working, that insight can move quickly through the organisation and the business can respond immediately.”
Picture a product launch gaining traction within days. An in-house analyst flags it to the head of that product line, who decides that afternoon to push harder. The loop from data received to decision taken closes in hours.
That speed helps explain why a growing number of marketers are insourcing analytics, SEO and performance capability.
They want to own their data and reduce agency dependency. Several flagged the risk of losing years of insight whenever an agency relationship ends.
But the research doesn’t point to a one-way trip. A leading automotive marketer leans heavily on brand building and his agencies, does comparatively little performance marketing, and the approach is working well.
His reasoning is philosophical: he prefers to invest in long-term brand building.
Respondents’ agency relationships tell a similar story.
Brand partnerships tend to last, often ten years or more. Performance relationships are more fluid, and marketers will switch if KPIs slip.
Several now prefer smaller specialist performance agencies to large traditional ones, which they find slower to move and short on platform expertise.
In-housing brings its own pressures.
Marketers are increasingly expected to be generalists across brand, digital, performance and data, and several respondents flagged the resulting capability gaps.
Smaller teams are most exposed, risking a drift from strategic to operational work.
Size varies widely: among respondents who shared their headcount, in-house teams average seven to eight people, but the range runs from one person to 38.
Whichever model a marketer chooses, the most effective set-ups have internal teams and agencies sharing data, co-creating strategy and reviewing performance together rather than working in silos.
“There isn’t a case here for agencies over in-house teams, or the reverse,” says McDowell.
“The question is whether the combination works for that particular marketer, and whether everyone involved is genuinely working as one ecosystem.”
That is probably the more useful way to frame the conversation. The best model is the one which puts the right capability where it can do the most good, and keeps it connected.
